K4CO4

K4CO4 is a semiconducting potassium-based oxide known for its structural complexity and metastable nature.

CKO
Crystal structure of K4CO4 (tetragonal, P42/n (No. 86))
Ground-state structure · Materials Project
Overview

About K4CO4

K4CO4 is a complex potassium-based oxide that exhibits semiconducting electronic properties. As a compound characterized by a significant number of reported structural variations in materials databases, it represents a subject of ongoing interest for researchers exploring unconventional stoichiometry in alkali metal oxides. Its existence above the thermodynamic hull suggests that it is a metastable phase, requiring specific synthesis conditions to stabilize its structure. This complexity makes it a notable, if challenging, candidate for fundamental studies in solid-state chemistry. Given its electronic nature, it is primarily investigated for its potential role in specialized chemical environments where alkali-rich oxide frameworks are required. The material serves as a case study for understanding the stability limits of highly basic oxide systems.

At a glance

Key Properties

Cross-validated computational properties for K4CO4, aggregated across 3 databases.

Band Gap

0.03–2.97 eV
Range across DFT structures

Energy Above Hull

0.161 eV/atom
Best (lowest) across sources

Stability

Above hull
2 DFT sources

Structures

37
3 databases, 11 space groups
Crystallography

Reported Structures

Lowest-energy structures reported for K4CO4, ranked by energy above hull.

Space GroupCrystal SystemBand Gap (eV)E above hull (eV/atom)E/atom (eV)Density (g/cm³)
P42/n (No. 86)tetragonal2.970.1609-5.3842.67
I-42m (No. 121)tetragonal1.440.1828-5.3632.01
C2 (No. 5)monoclinic2.030.1885-5.3572.44
Cm (No. 8)monoclinic2.100.1910-5.3542.44
I-42m (No. 121)tetragonal2.500.1945-5.3512.52
I-4 (No. 82)tetragonal1.790.1948-5.3512.51
Cm (No. 8)monoclinic1.600.2210-5.3242.21
Cm (No. 8)monoclinic0.910.2609-5.2842.05
P-43m (No. 215)cubic2.010.2825-5.2632.43
R3 (No. 146)trigonal2.340.2839-5.2612.45
R3m (No. 160)trigonal1.960.2847-5.2612.39
P1 (No. 1)triclinic0.030.8630-4.6821.67
Uses

Applications

Where K4CO4 is used.

Fundamental solid-state chemistry researchExploratory synthesis of alkali-rich oxides
Reference

Frequently Asked Questions

Common questions about K4CO4, answered from cross-validated data.

What is K4CO4?

K4CO4 is a semiconducting potassium-based oxide known for its structural complexity and metastable nature.

More questions
What is K4CO4 used for?
K4CO4 is used in fundamental solid-state chemistry research and exploratory synthesis of alkali-rich oxides.
What is the band gap of K4CO4?
K4CO4 has a DFT-computed band gap of 0.03–2.97 eV across 37 reported structures.
Is K4CO4 a metal, semiconductor, or insulator?
With a band gap up to 2.97 eV it is a semiconductor.
Is K4CO4 thermodynamically stable?
K4CO4 has a lowest energy above hull of 0.161 eV/atom (above hull).
What is the crystal structure of K4CO4?
The lowest-energy reported polymorph of K4CO4 is tetragonal symmetry, space group P42/n (No. 86).
What is the density of K4CO4?
The computed density of the ground-state structure of K4CO4 is 2.67 g/cm³.
How many polymorphs of K4CO4 are known?
37 structures of K4CO4 are reported across 3 databases, spanning 11 distinct space groups.
What elements does K4CO4 contain?
K4CO4 contains C, K, and O (3 elements).
Where does the data for K4CO4 come from?
K4CO4 data is cross-referenced from materials_project, jarvis, mpaloe.
Comparison

How It Compares

As a unique alkali-rich oxide, K4CO4 occupies a specialized niche in materials science. Unlike more common, thermodynamically stable ternary oxides, this compound exists in a metastable state, highlighting the intricate balance of ionic interactions within its lattice. It serves as a distinct example of how alkali metal-oxygen frameworks can be engineered, providing researchers with a reference point for exploring the limits of structural stability in non-standard oxide compositions.

Data sources & attribution
  • materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
  • jarvis — Data from JARVIS (NIST). Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020).
  • mpaloe — Data from mpaloe.

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